org.apache.hadoop.hbase.client

Class ScannerCallable

java.lang.Object

org.apache.hadoop.hbase.client.RegionServerCallable<T,org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.ClientService.BlockingInterface>

org.apache.hadoop.hbase.client.ClientServiceCallable<Result[]>

org.apache.hadoop.hbase.client.ScannerCallable

All Implemented Interfaces:

RetryingCallable<Result[]>

Direct Known Subclasses:

ReversedScannerCallable

@InterfaceAudience.Private
public class ScannerCallable
extends ClientServiceCallable<Result[]>

Scanner operations such as create, next, etc. Used by ResultScanners made by Table. Passed to a retrying caller such as RpcRetryingCaller so fails are retried.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	closed
protected Cursor	cursor
protected boolean	heartbeatMessage Saves whether or not the most recent response from the server was a heartbeat message.
protected int	id
protected boolean	instantiated
protected boolean	isRegionServerRemote
static org.slf4j.Logger	LOG
static String	LOG_SCANNER_ACTIVITY
static String	LOG_SCANNER_LATENCY_CUTOFF
protected boolean	renew
protected RpcControllerFactory	rpcControllerFactory
protected Scan	scan
protected ScanMetrics	scanMetrics
protected long	scannerId

Fields inherited from class org.apache.hadoop.hbase.client.RegionServerCallable

location, rpcController, stub

Constructor Summary

Constructors

Constructor and Description
ScannerCallable(ClusterConnection connection, TableName tableName, Scan scan, ScanMetrics scanMetrics, RpcControllerFactory rpcControllerFactory, int id)

Method Summary

Modifier and Type	Method and Description
protected void	checkIfRegionServerIsRemote() compare the local machine hostname with region server's hostname to decide if hbase client connects to a remote region server
int	getCaching() Get the number of rows that will be fetched on next
Cursor	getCursor()
HRegionInfo	getHRegionInfo() Returns the HRegionInfo for the current region
protected HRegionLocation	getLocationForReplica(RegionLocations locs)
protected RegionLocations	getRegionLocationsForPrepare(byte[] row) Fetch region locations for the row.
protected Scan	getScan()
ScannerCallable	getScannerCallableForReplica(int id)
void	prepare(boolean reload) Prepare by setting up any connections to servers, etc., ahead of call invocation.
protected Result[]	rpcCall() Run the RPC call.
void	setCaching(int caching) Set the number of rows that will be fetched on next
void	setClose() Call this when the next invocation of call should close the scanner
void	setRenew(boolean val) Indicate whether we make a call only to renew the lease, but without affected the scanner in any other way.

Methods inherited from class org.apache.hadoop.hbase.client.ClientServiceCallable

doGet, doMutate, setStubByServiceName

Methods inherited from class org.apache.hadoop.hbase.client.RegionServerCallable

call, getConnection, getExceptionMessageAdditionalDetail, getLocation, getPriority, getRow, getRpcController, getRpcControllerCellScanner, getStub, getTableName, setLocation, setRpcControllerCellScanner, setStub, sleep, throwable

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG_SCANNER_LATENCY_CUTOFF

public static final String LOG_SCANNER_LATENCY_CUTOFF

See Also:

Constant Field Values

LOG_SCANNER_ACTIVITY

public static final String LOG_SCANNER_ACTIVITY

See Also:

Constant Field Values

LOG

public static final org.slf4j.Logger LOG

scannerId

protected long scannerId

instantiated

protected boolean instantiated

closed

protected boolean closed

renew

protected boolean renew

scan

protected final Scan scan

scanMetrics

protected ScanMetrics scanMetrics

id

protected final int id

heartbeatMessage

protected boolean heartbeatMessage

Saves whether or not the most recent response from the server was a heartbeat message. Heartbeat messages are identified by the flag ClientProtos.ScanResponse.getHeartbeatMessage()

cursor

protected Cursor cursor

isRegionServerRemote

protected boolean isRegionServerRemote

rpcControllerFactory

protected final RpcControllerFactory rpcControllerFactory

Constructor Detail

ScannerCallable

public ScannerCallable(ClusterConnection connection,
                       TableName tableName,
                       Scan scan,
                       ScanMetrics scanMetrics,
                       RpcControllerFactory rpcControllerFactory,
                       int id)

Parameters:

connection - which connection

tableName - table callable is on

scan - the scan to execute

scanMetrics - the ScanMetrics to used, if it is null, ScannerCallable won't collect metrics

rpcControllerFactory - factory to use when creating RpcController

Method Detail

getLocationForReplica

protected final HRegionLocation getLocationForReplica(RegionLocations locs)
                                               throws HBaseIOException

Throws:

HBaseIOException

getRegionLocationsForPrepare

protected final RegionLocations getRegionLocationsForPrepare(byte[] row)
                                                      throws IOException

Fetch region locations for the row. Since this is for prepare, we always useCache. This is because we can be sure that RpcRetryingCaller will have cleared the cache in error handling if this is a retry.

Parameters:

row - the row to look up region location for

Throws:

IOException

prepare

public void prepare(boolean reload)
             throws IOException

Description copied from interface: RetryingCallable

Prepare by setting up any connections to servers, etc., ahead of call invocation. TODO: We call prepare before EVERY call. Seems wrong. FIX!!!!

Specified by:

prepare in interface RetryingCallable<Result[]>

Overrides:

prepare in class RegionServerCallable<Result[],org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.ClientService.BlockingInterface>

Parameters:

reload - force reload of server location

Throws:

IOException - e

checkIfRegionServerIsRemote

protected void checkIfRegionServerIsRemote()

compare the local machine hostname with region server's hostname to decide if hbase client connects to a remote region server

rpcCall

protected Result[] rpcCall()
                    throws Exception

Description copied from class: RegionServerCallable

Run the RPC call. Implement this method. To get at the rpcController that has been created and configured to make this rpc call, use getRpcController(). We are trying to contain rpcController references so we don't pollute codebase with protobuf references; keep the protobuf references contained and only present in a few classes rather than all about the code base.

Specified by:

rpcCall in class RegionServerCallable<Result[],org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.ClientService.BlockingInterface>

Throws:

Exception

getCursor

public Cursor getCursor()

getScan

protected Scan getScan()

setClose

public void setClose()

Call this when the next invocation of call should close the scanner

setRenew

public void setRenew(boolean val)

Indicate whether we make a call only to renew the lease, but without affected the scanner in any other way.

Parameters:

val - true if only the lease should be renewed

getHRegionInfo

public HRegionInfo getHRegionInfo()

Returns the HRegionInfo for the current region

Overrides:

getHRegionInfo in class RegionServerCallable<Result[],org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.ClientService.BlockingInterface>

getCaching

public int getCaching()

Get the number of rows that will be fetched on next

Returns:

the number of rows for caching

setCaching

public void setCaching(int caching)

Set the number of rows that will be fetched on next

Parameters:

caching - the number of rows for caching

getScannerCallableForReplica

public ScannerCallable getScannerCallableForReplica(int id)